Reduce precision rating to medium

This query won't always be a security problem, so it should have a lower
precision rating than `high`.

Author: egregius313

java/ql/src/Security/CWE/CWE-200/AndroidWebViewSettingsContentAccess.ql

@@ -5,7 +5,7 @@
  * @id java/android-websettings-content-access
  * @problem.severity warning
  * @security-severity 6.5
- * @precision high
+ * @precision medium
  * @tags security
  *       external/cwe/cwe-200
  */